OK here is my situation. I just set up my new setup and i'm getting a null in my bass response at my seat at around 70hz, its very noticable by ear. My fronts have two 6.5 woofers each and they can play 70hz and sound pretty good. I tried lowering the bass crossover in the receiver to 60 hz and i notice an improvement at 70hz because my fronts seem to help output some of the bass and it seems to be a smoother sweep of my test tones. The thing is my receiver doesnt have multiple crossover adjustments for each channel. I just have one setting. I was worried about the 60hz crossover as my center and surrounds are only advertised at 80hz-20k...as they will also be subject to the same crossover as the front... Playing 2ch stereo is no big deal as the other speakers are not used but during movies all channels are playing. I was wondering if there actually tends to be alot of bass directed to center and surrounds?? or mostly front and LFE channel. I was just concerned if it would be a problem if the center and rears got 60hz signals like actually damaging parts or something?? Or i could possibly set my fronts to large and keep the 80hz crossover but i am afraid they wont handle a full signal?? (IIRC Large speaker setting sends all frequencies to the speaker correct?) the towers are advertised to go to 50hz btw my setup is onkyo 313 AVR, fluance SX speakers and bic f12 sub.